Process for making carbon tetrachloride



y Aug. 4, 1931. P. s. BRALLIER ET AL PROCESS FOR MAKING CARBONTETRACHLORIDE Filed' June 30, 1922 AIIQQQ @MQUB nM-5 Edwmz J. `D Gerald,D 112119919110@ Patented Aug. 4, 1931 UNITED STATES PATENT orrics PAULS. BRALLIER, EDWARD J. DUNLAP AND GERALD D. MUGGLETON, OF NIAGARA FALLS,NEW YORK, ASSIGNORS TG NIAGARA SMELTING CORFORATION, OF 'NI- AGARAFALLS, NEW YORK, A CORPORATION OF NEW YORK Y PROCESS FOR MAKING CARBONTETBACHLORIDE Application ed June 30, 1922. Serial No. 571,977.v

This invention relates to the manufacture of carbon tetrachlorid, andhasfor its primary object to devise a simple, im roved and economicalprocess for such manu acture.

Another object is to improve the temperature control in certain steps ofthe process. More speciiically, this object involves the automaticcontrol of the temperature in certain portions of the apparatus employedto carry outl the process. l

Another object is to avoid the .use or formation of sulfur dichlorid.This is one great step in the elimination of waste in separating andpurifying the final product.

Another object is to separate the tetrachlorid by fractionaldistillation ifrom a mixture of itself and another ingredient having avery diiierent boiling point. More specifically, this` object involvesthe separation of the tetrachlorid from a mixture of itself and sulfurmonochlorid substantially 'free 'from car- A bon bisuliid and sulfurdichlorid.

Another object is by subdividing and segregating the reactions producingcarbon tetrachlorid, to obtain as end products, sulfur free from othersubstances, especially sulfur monochlorid; and carbon tetrachlorid freefrom other substances, especially carbon bisuliid and sulfur monochloridor dichlorid.

Another objectis to carry on the formation of carbon tetrachlorid in twostages, one of which has a product from which the carbon tetrachloridcan be readily and effectively distilled, and the other of which cantake the residue from the distillation and form new material to returnto the first stage and an end product suitable for Withdrawal in auseful and convenient form.

Further objects and advantages of the invention will become apparent asthe descrlp- /tion proceeds.

The accompanying drawing represents in a diagrammatic way one embodimentof ap.

tion

CS2 -l- 3Gl2= C0144- S2Cl2 (l) This is a practicable reaction, but byitself is undesirable because sulfur monochlorid 1s not a suitable endproduct; It is also limited by the serious objection to either carbonbisuld or sulfur dichlorid in the product. The boiling points of thesesubstances are:

CS2 46 C. CCI4 76.6 C. 52(3124 1380 C. SClz 59 C.

lt will be apparent that fairly pure carbon tetrachlorid can bedistilled from a mixture of carbon tetrachlorid and sulfur monochloriduntil nearly all the carbon tetrachlorid has been removedfrom theresidue, but that the presence of carbon vbisuliid would necessitate itsremoval rst and give carbon tetrachlorid with tWo impurities instead ofone.

Sulfur forms chlorin compounds containing higher proportions of chlorinthan sulfur monochlorid, and reference is often made to a substancecalled sulfur dichlorid, having the formula S012. Whether this substanceis in fact a mixture of sulfur monochlorid and sulfur tetrachlorid ornot, the further chlorination of sulfur monochlorid gives matcria'l re-:terred to herein 'for convenience as sulfur dichlorid, having a boilingpoint so near that of carbon tetrachlorid that separation by fractionaldistillation is exceedingly diiticult, and the resultant carbontetrachlorid contains large amounts of three impurities instead of asmall amount of one, which must all be eliminated by purification.

It will be apparent that it is essential to carry reaction (l) farenough to eliminate carbon bisulfid but not far enough to chlorinate thesulfur farther than the monochlorid.

The present invention involves the discovery that reaction (1'), stage lof the process, can be carried out in the liquid phase by bubblinggaseous chlorin through a liquid mass comprising at first carbon bisulidwith or Without some carbon tetrachlorid, in the presence of a suitablecatalyst, such as iron. The reaction is eXothermic and the boiling pointof the mass rises as the reaction proceeds. It is also possible tocontrol the reaction temperature automatically by the ebullition of themass, which is placed in a chlorinator 10 and subjected to the action ofchlorin through pipe 12. The vapors are condensed in a condenser 14,uncondensed gases pass- 1n oil through pipe 16, and the condensate beingyretu rned lto thechlorinator. .Control of the reaction, therefore,involves nothing but control ofthe injection of chlorin, which may befast or slow as desired, and the temperature-is substantially assatisfactory an indication 'of the, progress of the reaction as chemicalanalysis would be.

Chlorination of theniixture can safely continue to and a trifle beyondthe point correspendingV to the formula S2Cl2. The temperature is anexact indication, not of the heat developed but of the boiling point ofthe mixture because excessive heat is continually developed in the massand any excess is automatically absorbed iii-condenser 14. In practicethe temperature is observed and as soon A chlorid, which boils at 59degrees C.

The resultjof stage 1 is a mixture of carbon tetrachlorid and sulfurmonochlorid free from both carbon bisulfid and sulfur dichlorid, fromwhich an unusually 'pure grade of crude carbon tetrachlorid can bedistilled.

This is done in stage 2 in still 18 rectifying column 20, dephlegmator22, and condenser 24.-. The resultant carbon tetrachlorid is not onlyfree from carbon bisuliid and sulfur dichlorid but contains much lesssulfur monochlorid than it would if the invention required the residueto be sulfur monochlorid, as will be apparent hereinafter.

The residue of stage 2 is sulfur monochlorid with a fair percentage ofcarbon tetrachlord because 'the'distillation was limited `to tem'-peratures giving carbon tetrachlorid almost free of sulfur monochlorid,and, therefore, did not remove all the carbon tetrachlorid. Thissubstance vas an end product would be an expense to get rid of if theprocess was Acar-A ried out on a lar e scale, and, furthermore, thecarbon tetrac lorid must not be thrown away andwasted.

According to the invention, this residue is subjected to the followingreaction in-stage 3:

` The primary purpose of this stage is to eliminate sulfur monochlorid.Sulfur is a suitable end product, and carbon tetrachlorid the endproduct desired for the entire process, and as the boiling point ofsulfur is about 445 C.,

' one stage theseI can be separated very readily. But sulfur monochloridhas a higher boiling point the reaction vaporizes source 30 is runthrough line 32 under the.'

surface of thehot monochlorid.- The heat of art of the resulting carbontetrachlorid-carbon bisulfid'mxture, the vapors pass through line 34 tocondenser 36, and the condensate vis returned thru lines 38 and 32,while still more-carbonbisuliid is being run in; so that a body ofcarbon tetrachlorid-carbon bisulfidv mixture is built up in the still.When asmall ,excess of carbon bisulfid has been added, the carbonbisullid addition is stopped, andthe still is steam heated, causing themixture to boil l; the vapors being led to the condenser and thecondensate returned-to the still as during the bisuld addition. Thisreflux distillation iscontinued for a given period, to carry1 thereaction as far to the right aspossible, after which theA condensate isrun into chlorinating vessel 10 through line 40.

out of the still, more carbon bisulfid is run in under the surface ofthe sulfur-sulfur chlorid mixture remaining Vandthe resulting vapors arecondensed an returned tothe still as in the first carbon bisullidaddition.

l When practically all ofthe carbon bisulfidcarbon tetrachlorid mixturehas been drivenv When an amount of carbon bisulfd, approximately equalto that added in the first half of the operationhas beenrun in, thevolatile liquid.v is refluxed \for a s hort time and then distilled overinto chlorinator 10, leaving a residue of molten sulfur containing somesulfur monochlorid. This sulfur is drawn crude carbon tetrachlorid isrun vin under thel surface ofthemilk of lime from receiver 50 throughline 52, the heat generated b A the action of the lime on the sulfurchlorid. absorbed by cooling the still. When Sigg cient crude carbontetrachlorid has beenadded, the agitator is stopped, still steamheated,` and the purified carbon tetrachlorid distilled thru va rline'54to condenser 56, the condensate ing cau ht in receiver 58.

The inter-relation of the various stages such that-the objections to theprocess of any become desirable in. preparation for the next will beapparent. Because stage 1 stops at a point where carbon bisuld isentirely eliminated and no vsulfur dichlori'd formed, stage 2 is asimple two-component separation with-constituents of ver differentboiling points. Because the resi ue from stage 2 goes to stage 3 and thecarbon tetra.- chlorid therein back to stage 1 to complete a closedcycle, stage 2 can be stop ed at a point where the distillate is unusualy pure. Because the distillate from stage 3 goes back to stage 1 andshould contain a large proportion of carbon bisulfid it is possible toeliminate sulfur monochlorid from the residue of stage 3 by repeatedreflux distillation with carbon bisulfid without accumulating a mass ofundesirable material.

It should be noted that chlorin enters the systemby line 12 and leavesin the finished product from receiver 58. Aside from a slight loss intheform of sulfur monochlorid in the residue from stage 3 and in the formof calcium chlorid from the purification chamber 42, there is no loss ofchlorin. Carbon 'enters the system by supply 30. as carbon bisulfid andleaves it as carbon tetrachlorid in the finished product. Sulfur entersat supply 30 as carbon bisulfid and leaves as sulfur with the residuefrom stage 3. This does not represent consumption, however, as thesulfur from stage 3 is available for making more carbon bisulfd by anysuitable or well known process. Aside from a slight loss in the form ofsulfur monochlorid in the residue from stage 3 and in the crude carbontetrachlorid, there is no consumption 'of sulphur.

In case the sulphur from stage 3 is used to make more carbon bisulfidfor carrying out the above described process, the traces of sulfurmonochlorid left in it will come back as impurities in the carbonbisulfid, either as carbon tetrachlorid or` sulfur monochlorid or both.The step of making more carbon bisulfid from this sulfur, therefore,constitutes a part of the complete process involved in the invention,although per se it involves no novelty and may be carried out'in any oneof many well known ways. On this account, it has not been thoughtnecessary to indicate in detail the old and well known apparatusemployed for this ste the step being. indicated diagrammatical y by adotted line carrying the sulfur from stage 3 to unite with carbon andenter supply 30 as carbonbisulfid.

In combination with the rest of the process, this step has the novelfunction of saving any traces of sulfur monochlorid in the sulfur fromstage 3, which facilitates the process not only by saving waste at thispoint, but by making it unnecessary to carry the reaction of stage 3 asnear completion as would be commercially advisable if the sulfur were tobe used for other purposes,

The solubility of carbon bisulfid and sulfur dichlorid in carbontetrachlorid, and the difthat others may, by applying current knowledge,readily adapt the same for use under various conditions of service,without eliminating certain features which may properly be said toconstitute the essential items of novelty involvedwhich items areintended to be defined and protected by the following claims:

1. A processv for making carbon tetrachlorid which comprises, formingcarbon tetrachlorid and sulfur monochloridby the interaction of carbonbisulfid and chlorin, separating part of the carbon tetrachlorid fromthe sulfur monochlorid to form an end product, and forming more carbonJtetrachlorid by the inter-action of carbon bisulfid with the sulfurmonochlorid resulting from the preceding steps.

2. A process for making carbon tetrachlorid which comprises,4chlorinating carbon bisulfid far enough to obtain a mixture of carbontetrachlorid and sulfur monochlorid free from carbon bisulfid and sulfurdichlorid, subjecting the mixture to fractional distillation, removingthe chlorin from the residue with an excess of carbon bisulfid, removingsulfur and then chlorinating the remaining carbon bisuld.

3. The method of making carbon tetrachlorid which comprises, passingmaterial containing initially and essentially carbon bisulphide inbatches through a cycle compris ing a first reaction chamber, a still,and a second reaction chamber, introducing chlorin into the firstreaction chamber, withdrawing carbon tetrachlorid from the still only,and introducing carbon bisulfid and withdrawing sulfur from the secondreaction chamber, the carbon tetrachlorid formed in the second rcactionchamber going through the first reaction chamber on its way back to thestill.

4. The method of making carbon tetrachlorid employing sulfur as aconveyor of the chlorid, the steprepresented by the equationy carriedout by blowinggaseous chlorin into liquid carbon bisulfid, vcontrollingthe temperature by letting the masspboil, condensing the vapors, andreturning them to the mass and stopping as soon as the temperature o themass ceasesto rise.

8. In a process for making carbon tetra-l chlorid, the step of obtainingcarbon tetra chlorid containln a small percentage of impurities and freeom any catalyst by incom-` pletely distilling carbon tetrachloride vfroma mixturecontaining carbon tetrachlorid, sulfur monochlorid, and anon-volatile catalyst, p Y

9. In a pross ionmaking carbon tetrachlorid, the step of obtainingcarbon tetrachlorid containinga small ercentage of impurities bydistilling af mixture containingscarbon tetrachlorid .and sulfurmonochlorid only, and stopping the distillationl before all tlie carbontetrachlorid has been obtained.

10. In a process for making carbon Itetrachlorid, the steps of makingcrude" carbon tetrachlorid f containing. a small percentage ofimpurities by distilling a mixture composed substantiall entirely oftetrachlorid and sulfur monoch orid, stoppin the distillation beforeallthe carbon tetrac lorid has been obtained, and passing the residualcarbon te'traf chlorid without chemical'change thru a circuit in whichthe sulfur monochlorid is decomposed to form carbon bisuld and more,

carbon tetrachlorid, and the carbon bisullid isl decomposed to formsulfur monochlorid and still more carbon tetrachlorid, and returnin thesame to the still.

11. n a process for making carbon' tetrachlorid, the steps ofdecomposing a charge of carbon bisulfid, partly by reaction with sulfurmonochlorid, and subsequently by reaction in a` liquid bath with gaseouschlorin.

12. In a process for making carbon tetrachlorid, the steps ofdecomposing a charge of carbon bisuld, partlyby reaction with the sulfurmonochlorid, and'subsequently by reaction in a liquid bath with gaseouschlorin, the last reaction b'eing carrie to completion.

13. In a process for making carbon tetra- Achlorid, the elimination ofsulfur monochlo-v rid as an end product comprising the steps of carryingon the chlorination of carbon bisullid in a liquid bath in two separatestages, the first stage employing sulfur monochlorid, and the secondchlorin. 14; In a process for making carbon tetrachlorid, theelimination of sulfurA monochlorid as an end product comprising thesteps of carrying on the chlorination of carbon bisuld in a liquid bathin two stages, the first 'stage` employing sulfur monochlorid, and thesecond chlorin, an excess of carbon bisulid bein employed in the rststage to complete It le reduction of sulfur monochloridf l 15. A processfor making carbon tetra- ,chlorid from chlorin and carbon disulid,

which Acomprises circulatingv material containing initially andessentially carbon bisulphide in a closed circuit, and carrying out thereaction in said circuit in a plurality of stages, chlorinating carbonand reducing sulfur in'one stage, and chlorinating both carbon andsulfur in another stage.

16. A process for making( carbon tetrachlorid `from vcarbon and chlorin,which comprlses, clrculatmg sulfur 1n two closed circuits having acommon point, onecircuit including a separate re-action between sulfurand carbon to make carbon bisulfid, and a' joint reaction between carbonbisulfid and sulfur monochlorid to form rcarbon tetrachlovrid andsulfur, and the other circuit including said jointreaction, and areaction be- .tween carbon bisulfid in a liquid bath and chlorin to formcarbon tetrachlorid and sulfur monochlorid. l f

17. A process for making carbon tetrachlorid :fromy carbon and chlorinwhich comprises,

bonbisulfid and chlorin, (b) separating carbon tetrachlorid from sulfurmonochlorid by fractional distillation, (c) reducing sulfur monochloridwith carbon bisuliid, and (al) separating the other ingredients of'stage (c) from sulfur by distillation to return them to stage (a), andthe other circuit including Y stages (c) and (d) and (e) forming morecarbon bisuld fromcarbon and the sulfur from stagetal). l

18'. A process for making carbon tetrachlorid from carbon and chlorinwhich comprises, circulating sulfur in two closed circuits having twostages in common, one circuit including the stages of (a) forming carbontetrachlorid and sulfur monochlorid from carbon bisulfid and chlorin,(b) separating carbon tetrachlorid from sulfur monochlorid by frictionaldistillation, (c) reducing sulfur monochlorid with carbon'bisulid, and(d) separating the other ingredients o f stage (c) due containingsulphur chloride and carbon from sulfur by distillation to return themto tetrachloride,

and converting sulfur chloride stage (a), and .the other circuitincluding in the residue into carbon tetrachloride."

sta es (b) and (c) and (e) forming morey car from stage (d), the carbontetrachlorid not removed in stage (b) and that formed in stage (c) beingreturned without loss thru stage (d) to stage (a), and the compounds notremoved from sulfur in' stage (d) being returned without loss thru stage(e) to stage (c).

19. In a process for making carbon tetrachlorid, the elimination ofsulfur monochlorid as an end product comprisin i the steps of carryingon the chlorination o carbon bisu d in a liquid bath in two stages, thefirst stage employing sulfur monochlorid, and the second chlorin, anexcess of carbon bisuld being employed in the first sta e to completethe reduction of sulfur monoc lorid, the excess of carbon bisuliidmaking up the next charge for the process.

20. In a process for making carbon tetrachlorid, circulating a mass ofmaterial containing initially and essentially carbon bisulphide in aciosed circuit involving two chemical reactions, first, chlorination,and second, reduction by carbon disulfid, withdrawing carbontetrachloridby distillation after the first and before the secondreaction,

`and withdrawing sulfur as a residue after the second and before thefirst reaction.

21. In a process for making carbon tetrachlorid, circulating a mass ofmaterial containing intially and essentially carbon bisul phide 1n aclosed circuit involving two chemical reactions, first, chlorination,and second, reduction by carbon disulfid, withdrawing carbontetrachlorid by distillation after the rst and before the secondreaction, and withl drawing sulfur as a residue after the second andbefore the first reaction, an excess of carbon disulfid being employedduring the second-reaction to purify the sulfur before it is withdrawn.l

' 22. A process for preparing a substantially pure carbon tetrachloridAwhich comprises chlorinating to completion a charge of carbon bisuldewithout chlorination of the resulting sulfur chloride in the presence ofa nonvolatile catalyst, incompletely distilling to secure asubstantially pure fraction of carbon tetrachlorid, and treating theresulting residue toconvert sulphur chloride into carbon tetrachloride.A

23. A process of making carbon tetrachlorid which comprises chlorinatinga charge of carbon bisulide in the presence of a non-volatile catalystfar enough to obtain a mixture of carbon tetrachlorid and sulfurmonochlorid4 free from carbon bisulfid and sulfur dichlorid, subjectingthe mixture to a fractional distillation, whereby to secure a resi Inwitness whereof, we hereunto subscribe on bisuld from carbon and thesulfur our names this 26th dayiof June, 1922.

PAUL S. B ALLIER. EDWARD J. DUNLAP. GERALD D. MUGGLETON.

